Apparatus for the separation of materials of different densities



Oct. 17, 1967 A. R. VERBAERE 3,347,371

APPARATUS FOR THE SEPARATIONOF MATERIALS OF DIFFERENT DENSITIES Filed March 4, 1965 2 Sheets-Sheet 1 Q0 E i e Inverfior AR-VERBAERE fl g wumhmh 17, 1957 A. R. VERBAERE 3,347,371 APPARATUS FOR THE SEPARATION OF MATERIALS OF DIFFERENT DENSITIES Filed March 4, 1965 2 Sheets-Sheet 2 ET Q I FIGZ InVen+or A. R. VERBAERE "MM wnmAm-S United States Patent 3,347,371 APPARATUS FOR THE SEPARATION OF MATE- RIALS OF DIFFERENT DENSITIES Andre Rene Verbaere, Paris, France, assignor to Societe Anonyrne dite: Unitec, Paris, France Filed Mar. 4, 1965, Ser. No. 437,163 Claims priority, application France, Mar. 9, 1964, 966,685, Patent 1,397,307 Claims. (Cl. 209-172) It is known that minerals, at the moment of extraction, are mixed with tailings or with gangues of different density, which by necessity have to be separated from the minerals themselves in order to purify the extracted raw materials.

It is also known that one makes use of this difference in specific gravity which exists between the impurities and the minerals in order to obtain such a separation, be it by gravitation or by centrifugal acceleration. For this purpose one makes use of a medium with a specific gravity lying between that of the average specific gravity of the impurities and the average specific gravity of the mineral in question. Under the influence of either gravitation or of centrifugal acceleration, the lighter body will float in the media, whereas the heavier body will sink;

this well known process is called sink-float" or heavymedia or dense media process.

In accordance with the relative specific gravities of the bodies which one has to separate, one chooses a suspension liquid of intermediate density (an organic liquid for instance), or an aqueous suspension of certain finely ground particles of various materials. Materials commonly used for such a suspension are sand, magnetite or ferrosilicon, depending on the materials which one wants to separate.

The methods used for separating products of different specific gravities by means of the above processes are equally known, consisting in essence of inducing in a recipient a turbulent overflow of the separating medium loaded with the raw materials to be extracted. This whirling movement due to the overflowing creates a field of centrifugal acceleration which provides the separation effect.

The invention under discussion presents a more eflicient means of obtaining such an adjustable separation than that described above. This process consists mainly of the following: after having placed the mixture of solids into a suspension of intermediate density, a whirl is created by means of a pump preferably of the vortex-type, due to which the heavy fraction is separated from the light fraction, and is at the same time discharged by the action of the same pump, which has created said whirl.

The object of this invention is also to provide novel apparatus for carrying out the above mentioned process. This apparatus is essentially characterized by the fact that the rotation of the separating media is obtained by the self same pump which provides the discharge of the heavy fraction of the raw material which is being treated.

In an improved version, the apparatus covered by this invention incorporates two pumps preferably of the vortex-type, one of which is intended to discharge the light fraction of the mixture of solids being treated, by means of suction near the center of the apparatus; the other designed to create the field of centrifugal force which provides the separation, and at the same time the discharge of the heavy fraction of the solids to be separated, which portion is being discharged at the periphery of the apparatus. The feed, i.e. media containing the materials to be separated in suspension, can be fed into the apparatus in any manner desired, i.e. radially, axially, or even in certain cases, tangentially. In the case of the apparatus being fed tangentially, a slight speed-up of the whirl is produced due to the admixture of the feed.

With regard to the pump which provides the discharge of the light fraction of the product of separation, it may or may not contribute to the creation of the whirl, depending on whether it runs in the same direction as the pump which effects the discharge of the heavy fraction of the mixture.

In order to better establish the object of the invention, I shall, in order to illustrate the invention more in detail, without, however, limiting its characteristics in any way, give as an example of the functioning of this device the following description, which is documented by the attached drawings.

On this drawing:

FIGURE 1 represents, in cross section, the apparatus covered by this invention, as seen intersecting the axis of the two vortex-type pumps;

FIGURE 2 represents the apparatus, covered by this invention, installed in operating condition.

FIGURE 1 shows the feed pipe 1 which introduces the media containing the raw material into the body of the apparatus 2. The body of the apparatus has the general shape of a feed pipe is located tangentially to the cylinder and perpendicular to its axis. One of the ends of the cylinder 2a discharges into the volute 3 of a centrifugal vortex-type pump whose runner 4 is fitted with blades. This vortextype pump, designated as a whole by 6 is driven by an electric motor 7. The discharge of the material rejected by the pump is effected by the pipe 8.

The cylindrical body 2 of the apparatus has a rather large diameter. With respect to the intake of the vortextype pump discharging thelight fraction, in the center of the plate 222 which constitutes the end of the cylinder 2 opposite to pump 6, a circular hole has been incorporated which is fitted with a watertight flange 9 permitting pas-,

sage of a cylindrical pipe 10. This pipe is horizontal and can slide through this watertight flange 9 in such a fashion thatits end near the pump side '6 can be moved along the axis of the cylinder 2. The other end of this cylindrical pipe 10 is connected with a difluser Illa whose cross section is rapidly increasing. This diffuser constitutes the entry into the centrifugal vortex-type pump designated 11 as an assembly. This vortex-type pump is essentially the same as pump 6. It incorporates a runner 12 fitted with blades 13 and is driven by an electric motor 15. Its housing can slide on a rail 16 in order to permit the horizontal movement of the cylindrical pipe 10.

On FIGURE 2, it can be seen that the apparatus is fed from a hopper 17 whose shape is essentially conical and which directs the product toward the feed pipe 1. Between the hopper 17 and the inlet pipe a gate valve 18 is installed. The raw material to be separated is introduced into the hopper by means of a spout 19. The media used for the separation is brought to the hopper by means of two re-cycling pipes 20a and 20b. The feed pipes 8 and 14 connect with a recovery system shown schematically in FIGURE 2 and designated by 21a and 21b. The recovery system 21a is fed, by means of feed tube 14, a mixture containing the separating media and the lightweight fraction of the solids to be separated; the separating media is re-circulated by means of tube 20a and the lightweight fraction of the separated product is evacuated via 22a. The functioning of the installation 21a is the same, the recircuation tube being 20b, and the evacuation of the heavy weight fraction of the separated product taking place via 22b.

In order to operate the apparatus covered by this invention for the separation of a mineral from impurities, one chooses a media whose specific gravity (or density) cylinder with horizontal axis, and the.

is between the average specific gravity of the mineral to be extracted and the average specific gravity of the impurities to be discarded. The media can, for instance, consist of a suspension in water of magnetite granules of 20 to 300 microns. This media is fed into the hopper 17 and the products to be separated are fed to it by means of the spout 19. This mixture gets into the apparatus via pipe 1 and fills the cylinder 2.

The centrifugal vortex-type pump 6 driven by the motor 7 rotates the material contained in the cylinder 2 and furnishes the necessary energy to create a whirl in the interior of the cylinder, as well as for the discharge through the tube 8. This whirl creates a field of centrifugal acceleration in such a fashion that the lightweight fraction of the raw material has a tendency to stay in the center of the cylinder 2, Whereas the heavy fraction of the product to be treated has a tendency to locate near the periphery of the said cylinder. Pump 6 evacuates the material accumulated in the neighborhood of the cylinder walls, i.e., the heavy fraction of the material treated, mixed with the media. Pump 11, on the other hand, sucks from the cylinder 2 by means of tube 10 the material which is accumulated in the neighborhood of the axis of the cylinder, i.e., the lightweight fraction of the product to be separated, mixed with the separating media. The lightand heavy-weight fractions evacuated by pipes 8 and 14 are consequently brought to the recovery system. This system functions in the well known fashion, i.e., the suspension particles of the media are removed by means of screening, then the heavy, as well as the lightweight fraction of the product to be separated are washed, and eventually all particles suspended in the heavy media are recovered by magnetic separation. Thus the whole separating media is recovered, as for instance the magnetite, which can then be re-circulated by means of pipes a and 20b into the hopper 17.

The pump 6 has a direct influence on the whirl generated on the inside of the cylinder, and thus it is clear that the speed at which this pump rotates is one of the main parameters of regulation in this process of separation covered by this invention. On the other hand, the eflect of the pump 11 is indirect only, in view of the presence of the pipe 10 and of the diffuser 10a. However, the whirl created in the neighborhood of the blades 13 of the pump 11 is transmitted to a certain degree via the orifice of the pipe 10 to the interior of the cylinder. As a result, it is preferable to have both pumps, 6 and 11 rotate in the same direction, in order not to get a counter rotation to the whirl, but to co-ordinate and increase both pump effects. Furthermore, it has to be taken into consideration that the feed pipe arriving at an angle, as shown on the drawing, creates a slight whirl in itself due to the tangential introduction of the material. Thus-in order to obtain a better separation efliciency-it is preferable to have the pumps turn in such a direction as to increase said whirl created by pump 6 rather than to counteract it. The material introduced by pipe 1 is subjected to a helicoidal movement inside the cylinder 2 and then is subjected to suction by one of the two pumps. While the apparatus is operating, these exists on the inside of the cylinder 2 a zone of separation in the space where the suction of pump 11 is active. The criteria of the separation effected in the apparatus are determined on one hand by the choice of density of the separation media, and on the other hand, by the location of the zone of separation mentioned before, on the inside of the cylinder 2. It is known that one can modify the density of the media by diluting or re-concentrating the media suspension in the course of re-circulation and thus influence the relative quantity of the so-called float particles in relation to the so-called sink particles.

It is, however, also possible to influence the shape of the separating zone on the one hand, by slowing down the rotating speed of the two pumps in relation to each other, and on the other hand, by regulating the position of the pipe end 10 on the interior of the cylinder 2 by sliding the pump 11 along the rail 16. It is obvious that one of the great advantages of the apparatus-apart from the fact that it permits a very eflicient separation by means of the considerable energy which can be brought into action to this end by the centrifugal pump 6-is the very simple means of adjustment and, thus of modification of the characteristics of the heavy and lightweight fractions to be extracted from the raw material while the apparatus is operating.

It goes without saying that the above mentioned type of construction does not limit in any way the application of the apparatus to this specific purpose, but that any number of desirable modifications can be incorporated, without going beyond the scope of this invention. Particularly, the body 2 of the apparatus does not have to be only cylindrical, but it might be cone-shaped, and its axis does not necessarily have to be horizontal.

What I claim is:

1. A device for separating particulate solid products of different specific gravities when mixed with a fluid product having a specific gravity intermediate that of said solid products, said device comprising a receiving chamber (2) provided with an inlet (1) for introducing said products into said chamber, a first centrifugal pump (6) at one end (2a.) of said receiving chamber having a runnor (4) positioned to impart a swirling motion to the products Within haid receiving chamber, said first pump being provided with an outlet (8) positioned to receive products driven to the outer portion of said chamber by said swirling motion, and a second centrifugal pump (11) having an axial inlet pipe (10) connected to withdraw through the end (2b) of said chamber opposite said first pump products located in an area within said chamber at the center of the swirling motion caused by said first pump, said second pump being provided with an outlet (14) for receiving products withdrawn from said chamber through said inlet pipe.

2. A separator as claimed in claim 1 comprising means for adjusting the distance between the first pump and the receiving chamber end of the inlet pipe of the second pump, while leaving the volume of flow through said second pump unaffected.

3. A separator as claimed in claim 1 comprising means for adjusting the speed of each pump independently of the other pump.

4. A separator as claimed in claim 1 in which both pumps rotate in the same direction.

5. A separator as claimed in claim 1 in which said pumps are of the vortex type.

References Cited UNITED STATES PATENTS 2,255,807 9/1941 Plumlee 2O9211 2,635,548 4/1953 BraWley 103-403 2,739,709 3/ 1956 Kaiser 209-144 2,874,642 2/1959 Forrest.

2,996,187 8/1961 Payne 209-2l1 3,171,357 3/1965 Egger 103-103 3,196,799 7/1965 Loss 1O3103 M. CARY NELSON, Primary Examiner.

HENRY T. KLINKSIEK, Examiner, 

1. A DEVICE FOR SEPARATING PARTICULATE SOLID PRODUCTS OF DIFFERENT SPECIFIC GRAVITIES WHEN MIXED WITH A FLUID PRODUCT HAVING A SPECIFIC GRAVITY INTERMEDIATE THAT OF SAID SOLID PROUDCTS, SAID DEVICE COMPRISING A RECEIVING CHAMBER (2) PROVIDED WITH AN INLET (1) FOR INTRODUCING SAID PRODUCTS INTO SAID CHAMBER, A FIRST CENTRIFUGAL PUMP (6) AT ONE END (2A) OF SAID RECEIVING CHAMBER HAVING A RUNNER (4) POSITIONED TO IMPART A SWIRLING MOTION TO THE PRODUCTS WITHIN SAID RECEIVING CHAMBER, SAID FIRST PUMP BEING PROVIDED WITH AN OUTLET (8) POSITIONED TO RECEIVE PRODUCTS DRIVEN TO THE OUTER PORTION OF SAID CHAMBER BY SAID SWIRLING MOTION, AND A SECOND CENTRIFUGAL PUMP (11) HAVING AN AXIAL INLET PIPE (10) CONNECTED TO WITHDRAW THROUGH THE END (2B) OF SAID CHAMBER OPPOSITE SAID FIRST PUMP PRODUCTS LOCATED IN AN AREA WITHIN SAID CHAMBER AT THE CENTER OF THE SWIRLING MOTION CAUSED BY SAID FIRST PUMP, SAID SECOND PUMP BEING PROVIDED WITH AN OUTLET (14) FOR RECEIVING PRODUCTS WITHDRAWN FROM SAID CHAMBER THROUGH SAID INLET PIPE. 